1. Field of the Invention
The invention relates to a microphone, and in particular to a microphone module for a communication apparatus.
2. Description of the Related Art
Cellular phone can be widely divided into a bar type and a fold type. The fold type cellular phone has an advantage over the bar type one including better voice quality due to the microphone closer to the user's mouth. This is pronounced when the size of the telephone is reduced because the microphone in a bar type moves further from the user's voice. No matter what type of the cellular phone, however, thinness of the cellular phone is limited due to the need to maintain a distance between the front side of the phone housing and the printed circuit board (PCB) therein for disposing the microphone.
FIG. 4 is a cross section of a bar type cellular phone according to the related art. The cellular phone 400 comprises a phone housing 402, a phone PCB 406 and a liquid crystal display (LCD) device 410. The front side of the phone housing 402 has an acoustic hole 403 and a display window 405. A plurality of keypads 404 is disposed on the front side of the phone housing 402. The phone PCB 406 is placed in the phone housing 402 and has a front side 406a facing the keypads 404 and a rear side 406b. The LCD device 410 is placed in the phone housing 402, corresponding to the display window 405 and coupled to the phone PCB 406. Generally, to achieve a thinner phone design, electronic components (not shown) are all disposed on the same side of the phone PCB 406 opposing the keypads 404 (i.e. the rear side 406b of the phone PCB 406). However, in order to maintain optimum acoustic performance, the acoustic hole 403 of the phone 400 must be located at the front side of the phone housing 402 so as to near the user's mouth. Accordingly, a microphone 408 is usually mounted on the front side 406b of the phone PCB 406 and corresponds to the acoustic hole 403. As a result, thinness of the cellular phone 400 is limited due to the need to maintain a space between the front side of the phone housing 4020 and the phone PCB 406 for disposing the microphone 408.
Additionally, a typical microphone has a holed electret sensor placed in a housing. Two pins are coupled to the sensor and pass through the housing for electronically connecting to external circuits. However, as the development of acoustic technology, such as echo cancellation, noise suppression and beam-forming, such a microphone is no more to meet current and future demands.
Thus, there exists a need in the art for design of an improved microphone structure and a novel microphone arrangement which can solve the mentioned problems.